An employer faces a minimum wage control where it cannot pay its workers less than $10.25 an hour. The employer knows that the workers value the jobs and are willing to work even at much less. The employer decides to offer them the minimum wage, but successfully stops other sellers of work uniform from sell uniforms to its workers so that he can charge more for the ones he sells. This is an example of

a. Fraud

b. Exclusion

c. Tying

d budling